Detachable blade bit



May 12, 1936.

L. A. PAYNE ET AL 2,040,263

DETACHABLE BLADE BIT 2 Sheets-Sheet 1 Filed Feb. 4, 1933 I INVENTORS. g- LESLIE A. LAYNE & HAROLD CBLOCK.

BY vi/25116 cw ATTORNEYS.

May 12, 1936 L. A LAYNE ET AL I 2,040,263

DETACHABLE BLADE' BIT Filed Feb. 4, 1933 2 Sheets-Sheet 2 JINVENTORS. LESLIE A. L4 YNE 8: Hmzow CBL OCK.

A'TTORNEYS.

Patented May 12 1936 UNITED PATENT OFFICE DETACHABLE BLADE BIT Application February 4, 1933, Serial No. 655,198

4 .Glaims.

Our invention relates to well drills, and more particularly to the type of scraping bits known generally as fishtail bits.

It is an object of our invention to provide a fish tail bit wherein the *bladeportion-thereof is "detachable andto provide means in-such a structure for easily and securelypattachingtm -blade to the head.

It is a further object ofthe invention to provide means'ior securing the blade in position, which will allowfor adjustment due to wear, 'so that the blade will constantly be held rigid even-after wear hasoccurred.

Another object of the invention is to provi'de means for securing the blade frictionally in position, and, in addition thereto, to provide a holding means which will hold the-blade positively against removal of the-blade-irom the head.

The invention further resides in the general arrangementandconstruction of the blade and the-head an understanding of which will appear more clearly from the description which follows.

In the drawings herewith, Fig. 1 is a side View showing the blade in elevation and the head in central longitudinal section, a portion of the shank of the bit being broken away.

Fig. 2 is a side elevation of the blade detached from the head.

Fig. 3 is a top plan view of the blade shown in Fig. 2.

Fig. 4 is an edge view of the blade member shown in Fig. 2.

In constructing our improved bit we form a head I which may be cylindrical in outline but having a reduced upper end 2 for connection with the drill stem. Instead of the usual upwardly tapered shank we provide a downwardly tapered box 3 in the neck 2 of the bit to connect with a tool joint or drill collar, by means of which connection is made with the drill stem. At the lower end of the threaded socket 3 is a chamber 4, having a lower shoulder 5 therein, upon which the blade attaching means may contact.

The lower end of the head is formed with a transverse slot 6 therein to receive the blade I.

This slot is extended upwardly at each side, as

shown at 8, to receive the upwardly extending wings 9 on the blade. The bit has an axial opening l0 therein extending from the chamber 4 through to the lower end. This opening is tapered upwardly so as to form a wedging fit with the shank H of the blade.

The blade 'I is of the usual fish tail form having its lower end divided at l2 midway of the 55 width thereof and one edge of the blade is curved in one direction and the other edge in the other, both sides of the blade being extended in a forward directionrelative to the rotation of the bit. The shank H of the bit is tapered upwardly to fit the opening or socket l0 and is of sufiicient 5 length to project upwardly to a point spaced somewhat from the upper shoulder 5, as will be seen in Fig. 1.

The shank has an axial recess at its upper end, threaded at I3 to receive a locking bolt Hi. It will 10 be noted that when the shank II of the blade is in .a wedging position within the opening or socket l ii, the upper end I 5 of each wing of the blade isspaced downwardly from the upper end of the openingzB into which it fits. Likewise, the upper 15 portion iii of the blade,adjacent the lower end of the head is spaced from the head so that in case of wear of the shank in the socket the blade may be wedged further upwardly into position without coming to a stop against the upper por- 20 tions of theslot in the head which receives the blade.

The locking bolt l4 may be screwed in place in the upper end of the shank by tools inserted downwardly through the upper socket 3 in the 25 head. We contemplate the use of an annular plate or washer I! having its lower end fitted within the opening I0 and adapted to receive the upper end of the bolt. We may provide a looking ring I8 between the head of the bolt and the plate or washer l1, so that when the bolt is tightened in the socket [3 it may serve to draw the shank more securely in position in the head and prevent any tendency of the bit to be lost in the hole. 35

The flushing fiuid in this tool will pass from the chamber 4 through downwardly inclined water courses shown at IS in dotted lines in Fig.

1. It is to be understood that there are two oppositely inclined water courses one on each 40 side of the head, which tend todischarge the flushing fluid in front of the cutting edges of the blade.

The advantage of this construction lies in the fact that it is easily and quickly secured in po-. 45 sition. The blade is inserted into the position shown in Fig. 1 and driven in place with a wedging fit of the shank in the socket ID. The wings 9 of the blade fit within the slot but have no action to secure the blade in position, the shank H being relied upon entirely to hold the blade in place. The locking bolt M is then inserted downwardly through the socket 3 and through the washer I1 and screwed within the threaded recess I3 in the shank. As the bolt is tightened in position it will be seen that it will exert a further pull upon the blade, tending to move it into a rigid fit with the head from which it will not be removed in operation.

Due to the fact that the driving torque of the head relative to the blade is taken up by the sides of the slot 8, into which the blade fits, there will be no relative rotation of the blade relative to the head. Furthermore, due to the fact that the weight of the head rests upon the blade there will be no heavy force tending to remove the blade from the head. The driving fit of the tapered shank H in the socket [0 will be entirely sufiicient to hold the same against removal. The locking bolt I4 is an extra provision which is made to prevent any accidental loosening of the shank in the socket. It is, therefore, simply a safety measure but ordinarily will not be necessary. It will be easily seen that when the blade is to be removed the bolt may be unscrewed and withdrawn and a driving force exerted upon the upper end of the shank II, forcing the blade from its position in the head so that it may be replaced by a newly sharpened blade.

Having described our invention, what we claim as new is:

1. A fish tail well drill including a head having a diametrical slot at its lower end, an axial upwardly-tapered socket in said head, a shoulder in said head at the upper end of said socket, a fishtail blade, a tapered shank thereon shaped to form a Wedging fit in said socket when the upper end of said blade is spaced below the upper end of said slot, a plate in said head engaging said shoulder, and a bolt extending through said plate and screwed within the upper end of said shank to secure said blade to said head.

2. A fish tail well drill including a head having a diametrical slot at its lower end, upward extensions in said slot at its ends, an axial upwardly-tapered socket in said head, a shoulder in said head at the upper end of said socket, a fishtail blade, a tapered shank thereon shaped to form a wedging fit in said socket when the upper end of said blade is spaced below the upper end of said slot, lateral, upwardly extending wings on said blade fitting within said extensions in said slot, adapted to take the driving torque from said head in the rotation of the drill, and means to fix said blade in rigid engagement with said head.

3. A fish tail Well drill including a head having a diametrical slot at its lower end, an axial upwardly-tapered socket in said head, a shoulder in said head at the upper end of said socket, a fishtail blade, a tapered shank thereon shaped to form a wedging fit in said socket when the upper end of said blade is spaced below the upper end of said slot, channels for flushing fluid in said head extending from said shoulder downwardly on each side of said blade to discharge on the advancing sides of said blade above the cutting edges thereof, and means to fix said blade in rigid engagement with said head.

4. A fish tail bit for use with rotary drill stems including a head, a blade fitting within a diametrical slot at the lower end of said head, an upper threaded socket in said head to receive the drill stem, an axial opening through said head communicating with said socket and forming a shoulder at the lower end of said socket, a central upwardly tapered shank on said blade having a frictional fit in the opening in said head, means to hold said blade in said head including a plate on said shoulder closing the upper end of said opening, and a cap screw accessible through said socket and engaging through said plate to screw into said shank.

LESLIE A. LAYNE. HAROLD C. BLOCK. 

